If you want all the party effects to work on you, you need to be either, near the leader or be the leader. Like, if you are in Flaris and the leader is in Darkon, you wont get any boosts from the skills, but if you are the leader, you get the boosts
As for the lvl 45 deal, its a bit money consuming, but overall it gets you all the skills faster, and you dont have to worry about lvling hte party at all.